Cellskador

Cellskador (cell injuries) describe disruptions in cell structure and function caused by harmful stimuli. They are a central concept in pathology and biology, spanning reversible and irreversible changes that can affect any tissue. The severity and duration of the insult, along with the cell’s resilience, determine whether injury is reversible and what outcomes may follow.

Common causes include physical injury (trauma, heat, cold), chemical toxins and drugs, hypoxia and ischemia, infectious agents, immune-mediated damage, genetic defects, and aging. Reversible injury is often marked by cellular swelling and membrane blebbing; if the insult persists, injury progresses to irreversible damage and cell death. The outcome depends on the cell type and the availability of energy and substrates for repair.

Mechanisms involve depletion of ATP, mitochondrial dysfunction, dysregulation of calcium homeostasis, oxidative stress with reactive oxygen species, and disruption of plasma and organelle membranes. Morphologically, reversible injury shows swelling and organelle changes, while irreversible injury leads to loss of membrane integrity, leakage of intracellular contents, and activation of cell death pathways such as apoptosis or necrosis. Autophagy can be induced as a cellular stress response and may serve as a survival mechanism in some contexts.

Clinical relevance and assessment: cellular injury underpins many diseases, including myocardial infarction, stroke, liver injury from toxins, and sepsis. Diagnosis relies on histology, tissue biomarkers, and imaging; in research, cell injury is studied using various in vitro and in vivo models. Prevention and treatment aim to remove the cause, restore perfusion and oxygenation, and limit secondary damage through supportive care or targeted therapies where available.